Polymers of carbon monoxide and ethylenically unsaturated hydrocarbons have been known for some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators, e.g., peroxy compounds. U.K.1,081,304, discloses the production of similar polymers of higher carbon monoxide content in the presence of alkylphosphine complexes of palladium salts as catalyst. Nozaki extended this reaction to produce linear alternating polymers in the presence of arylphosphine complexes of palladium moieties and certain inert solvents. See, for example, U.S. Pat. Nos. 3,689,460 and 3,694,412.
More recently, the class of linear alternating polymers of carbon monoxide and ethylenically unsaturated hydrocarbons has become of greater interest in part because of the greater availability of the polymers in quantity. Production of this class of polymers, also known as polyketones or polyketone polymers, is illustrated by a number of Published European Applications including 121,965 and 181,014 and by copending U.S. patent application Ser. No. 930,468 filed Nov. 14, 1986. These references illustrate the production of linear alternating polymers of carbon monoxide and ethylenically unsaturated hydrocarbons in the presence of catalyst compositions formed from a compound of palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa less than about 6 and a bidentate ligand of phosphorus, arsenic or antimony.
In general, these polymerization catalyst compositions preferably are formed, inter alia, from a bidentate ligand of phosphorus, particularly a bis(phosphino)alkane, and best results are obtained when the catalyst composition is formed from a 1,3-bis(phosphino)propane. Phosphine ligands such as 1,3-bis(diphenylphosphino)propane and 1,3-bis[di(2-methoxyphenyl)phosphino]propane are illustrative of this class of bis(phosphino)propanes. While these catalyst compositions are efficient in catalyzing the production of the linear alternating polymers, it is desirable to provide even more active catalyst compositions. Copending U.S. patent application No. 208,948, filed Jun. 20, 1988 and now U.S. Pat. No. 4,877,861, discloses a more active catalyst composition wherein the phosphine ligand is a 1,3-bis(phosphino)propane having two additional hydrocarbyl substituents at the 2 position of the propane moiety, most preferably 2,2-dimethyl-1,3-bis[di(2-methoxyphenyl)phosphino]propane. However, these phosphino compounds are produced in very low yields by the usual reactions of a 1,3-dihalopropane, substituted on the 2 position, and a substituted phosphide having an alkali metal bonded to the phosphorous atom.